fix: #3673 - API responds with Request body is too large

[louis-jan]

Describe Your Changes

This addresses the issue where the Jan API server gates requests based on body size, rejecting any larger than 1MB. This PR increases the accepted request body size and also handles errors gracefully.

I'm trying to integrate OpenAI LLMs like, gpt-4-turbo, gpt-4o...etc to integrate with LaVague-QA framework for Test Automation. While LaVague is sending request to the LLM running in Jan.AI is responding with "Request body is too large" error.

Steps to Reproduce

1.Download the LLM gpt-4-turbo OR gpt-4o using Jan.AI interface
2.Make an API call to LLM (gpt-4-turbo OR gpt-4o)
3.Observe the response returned "Request body is too large"
Note: Attaching the API request body.

Screenshots

Error handling

Succeed

Fixes Issues

• Fixes bug: API responds with "Request body is too large" #3673

Code changes

1. core/src/node/api/restful/helper/builder.test.ts:

   • Added a new test case to check error handling when the status is not OK (400).
   • The test mocks a 400 status response and verifies that the error is properly forwarded.

2. core/src/node/api/restful/helper/builder.ts:

   • Modified the error handling in the chatCompletions function.
   • Instead of just logging the error and sending a 400 status, it now forwards the complete error response (including status code, headers, and body) to the client.

3. server/index.ts:

   • Added a bodyLimit configuration to the Fastify server initialization.
   • Set the body limit to 100MB (104,857,600 bytes), up from the default 1MB.
   • Added comments explaining the rationale for this limit, citing OpenAI's file size limits for various endpoints.

These changes improve error handling and reporting in the API, and increase the maximum allowed request body size to accommodate larger file uploads for certain AI model endpoints.

[github-actions]

Barecheck - Code coverage report

Total: 62.61%

Your code coverage diff: 0.05% ▴

Uncovered files and lines

File	Lines
core/src/node/api/restful/helper/builder.ts	45, 52-53, 61, 100, 116-117, 131-132, 175, 205, 250, 271, 284, 287, 290, 326-327, 335-336, 341, 346

[dan-menlo]

I see - this allows us to accept Vision and Speech in the future. Thanks @louis-jan!